I just finished a great tutorial on using Git. If you are interested it is on Lynda.com. Unfortunately, Lynda.com is not free but I highly recommend her site as it has taught me so much. Kevin Skoglund, the author of the video , does a masterful job at taking a topic that is complex and confusing and making it easy to digest by breaking it down into small logical chunks.
During this video I had to constantly enter my username and password while using github as my remote repository. You can totally avoid this and never have to enter your username and password again if you use SSH. This link will show you how to accomplish that on Mac, Windows or Linux. Enjoy.